Cutting oil removal by continuous froth flotation using an extended surfactant under microemulsion conditions

Abstract

The objective of this study was to remove cutting oil by continuous froth flotation using an extended surfactant under microemulsion conditions. The froth flotation experiments were carried out to observe the removal efficiency of cutting oil under three types of microemulsions. Branched alcohol propoxylate sulfate sodium salt (Alfoterra 145-3PO), an extended surfactant was used to form microemulsions with cutting oil in both the phase behavior and froth flotation studies. The effects of surfactant concentration, salinity, and oil-to-water ratio on the phase behavior were investigated in order to determine the compositions required to obtain various types of microemulsions as well as the ultra-low interfacial tension conditions. In the froth flotation experiments, the effects of surfactant concentration, salinity, and hydraulic retention time (HRT) on the oil removal were examined. The system with 0.3 wt.% Alfoterra, 10 wt.% NaCl, and 500 ppm oil content at 0.30 L/min air flow rate, 31 cm foam height, and 20 min HRT gave the highest oil removal of 83%. The results showed that cutting oil removal in the Winsor III microemulsion condition was higher than those in the Winsor I and Winsor II microemulsion regions.